Priority effects and competition by a native species inhibit an invasive species and may assist restoration

Selecting native species for restoration is often done without proper ecological background, particularly with regard to how native and invasive species interact. Here, we provide insights suggesting that such information may greatly enhance restoration success. The performance of the native vine, Pueraria lobata, and that of the invasive bitter vine, Mikania micrantha, were investigated in South China to test how priority effects (timing and rate of germination and seedling growth) and competition (phytochemical effects and competitive ability) impact invasive plant performance. We found that, in the absence of competition, the germination rate of M. micrantha, but not of P. lobata, was significantly affected by light availability. P. lobata seedlings also performed better than those of M. micrantha during early growth phases. Under competition, negative phytochemical effects of P. lobata on M. micrantha were strong and we found M. micrantha to have lower performance when grown with P. lobata compared to when grown by itself. Relative interaction indexes indicated that, under interspecific competition, P. lobata negatively affected (i.e., inhibited) M. micrantha, whereas M. micrantha positively affected (i.e., facilitated) P. lobata. Higher photosynthetic efficiency and soil nutrient utilization put P. lobata at a further advantage over M. micrantha. Field trails corroborated these experimental findings, showing little recruitment of M. micrantha in previously invaded and cleared field plots that were sown with P. lobata. Thus, P. lobata is a promising candidate for ecological restoration and for reducing impacts of M. micrantha in China. This research illustrates that careful species selection may improve restoration outcomes, a finding that may also apply to other invaded ecosystems and species.     

蕨类植物叶绿体rps12基因的分子进化研究

以68种蕨类植物和2种石松类植物的rps12基因为对象,在系统发育背景下,结合最大似然法,使用HyPhy和PAML软件对该基因进行进化速率和适应性进化研究。结果显示:位于IR区的外显子2~3,其替换率明显降低,rps12基因编码序列的替换率也随之降低,且rps12基因密码子第3位的GC含量明显升高;在蕨类植物的进化过程中,3′-rps12更倾向定位于IR区,以保持较低的替换率;rps12基因编码的123个氨基酸位点中,共检测到4个正选择位点和116个负选择位点。研究结果表明基因序列进入到IR区后,显示出降低的替换率;强烈的负选择压力表明RPS12蛋白的高度保守性以及rps12基因的功能和结构已经趋于稳定。     

The effect of grazing on winter survival of midday gerbil (Meriones meridianus) of different genders

The objective of this study was to investigate the effects of grazing on midday gerbil (Meriones meridianus) population characteristics and survival of animals of different genders. The experiment used a randomized complete block design and was conducted in Alxa Left Banner, Inner Mongolia, China, in 2002 (The agricultural reclamation plots set up in 1994). From April 2006 to October 2010, midday gerbils were live‐trapped in 3 light grazing plots, 3 overgrazed plots, and 3 grazing exclusion plots. The quantity of vegetation was investigated in the two different grazing intensity areas and grazing exclusion area to determine the relationship between gerbils and plant food availability. The results suggested that there was higher gerbil density, individual body mass, and daily body mass growth rate in the grazing exclusion sites than the other sites across the whole year. Females had higher survival in grazing exclusion areas than in other treatments, but the males’ survival showed the opposite pattern. Our results indicated that grazing negatively influenced the midday gerbil population by reducing food availability. Grazing influenced the survival rates of male midday gerbils positively, but had negative effects on females. The reason for gendered differences in survival rates of midday gerbils requires further investigation.     

Physiological and metabolomic responses of bermudagrass (Cynodon dactylon) to alkali stress

Bermudagrass (Cynodon dactylon) is a widely used warm‐season turfgrass species with superior stress tolerance except for cold. In this study, a comparative analysis of the responses to alkali stress in bermudagrass at the physiological and metabolomic levels were performed. Mild alkali with relatively low pH slightly inhibited growth of bermudagrass as evidenced by lower electrolyte leakage, more rapid growth and higher survival rate when compared to moderate and severe alkali treatments. Moreover, the amount of 37 metabolites including amino acids, organic acids, sugars and sugar alcohols were modulated by the alkali treatments. Among them, 15 metabolites were involved in carbon and amino acid metabolic pathways. Under mild alkali stress, bermudagrass possibly slowed down metabolisms to maintain basic growth. However, moderate and severe alkali‐stressed plants accumulated significantly higher amount of carbohydrates which might result in carbon starvation. Taken together, alkali stress had severely inhibitory effect partially due to combined ionic stress and high pH stress. These results suggested that bermudagrass employed different strategies in response to alkali stresses with different pH and ionic values.     

An Efficient Plant Regeneration System of <i>Hydrangea bretschneideri</i> Dipp via Stem Segments as Explants

Hydrangea bretschneideri Dipp is a highly popular ornamental plant for garden decoration. Genetic engineering technology has been successfully used in many plant species, but it is limited in Hydrangea. Here we established an efficient regeneration system by using stem segments as explants for the first time. In our study, the plant growth regulators (PGRs) were evaluated at the different regeneration processes, including axillary shoots regeneration and root induction. We found that the optimal concentration for axillary buds’ induction was 2.0 mgL⁻¹ 6-BA and 0.5 mgL⁻¹ 1 IAA, its highest induction rate was 70%. Moreover, the highest axillary shoots proliferation coefficient was 10.7 on the Murashige and Skoog (MS) medium with 2.0 mgL⁻¹ 6-benzyladenine (BA), 0.2 mgL⁻¹ indole-3-butyric acid (IBA), and 1.0 mgL⁻¹ gibberellin A3 (GA3). The highest frequency of root induction was 80.0 ± 0.06% by culturing the elongated shoots in 1/2 MS medium containing 0.1 mgL⁻¹ IBA. In summary, our study will provide an effective technology for large-scale propagation and important pathway for promoting the popularization and application of Hydrangea bretschneideri Dipp.     

Phenotypic and genetic dissection of cadmium accumulation in roots,nodes and grains of rice hybrids

Plant and Soil - Rice accumulates higher levels of cadmium (Cd) in grain than other cereals, and hybrid rice varieties cover around half of the total rice area in China. Therefore, understanding...     

Feeding of Burbot Lota lota in Modern Conditions of the Kuybyshev Reservoir

Journal of Ichthyology - The feeding of burbot Lota lota was studied in the modern conditions of the Kuibyshev Reservoir. With the decrease in the abundance of ruff Gymnocephalus cernuus in the...     

Assessment of risk factors for postoperative cognitive dysfunction after coronary artery bypass surgery: a single-center retrospective cohort study

Aim: To find out risk factors for postoperative cognitive dysfunction (POCD) after coronary artery bypass grafting (CABG), and to provide basis for clinical prevention of POCD. A total of 88 patients who underwent CABG were surveyed with Telephone Questionnaire (TICS-M) for their cognitive impairment after 3, 7, 21, 90, 180 days post-surgery. The occurrence of POCD was diagnosed by Neuropsychological Battery which included Vocabular Learning Test (VLT), Wisconsin Card Sorting Test (WCST), Trail Making Test (TMT) and Symbol Digit Modalities Test (SDMT). The preoperative, intraoperative and postoperative risk factors were assessed by the χ² or t test. Multivariate analysis was used to study the correlation between the risk factors and the occurrence of POCD. Age, aortic plaque, carotid artery stenosis, cerebrovascular disease, anesthesia time, the rate of decline in intraoperative hemoglobin concentration (ΔHb) and systemic inflammatory response syndrome (SIRS) score on postoperative day 2 had statistically significant (P<0.05) influence on the occurrence of POCD. Aortic plaque, carotid artery stenosis, anesthesia time and SIRS score (odds ratio (OR) value > 1, P<0.05) are the risk factors for POCD. The incidence of day-21 and -180 POCD was approximately 26.1 and 22.7%, respectively.